Hi I'm using OsCommerce and I am hosting with Ace-Host. I'm using a dedicated due to the amount of websites I have and the cost overall is great. The only kind of support they have is via email support. They don't talk on the phone, but if you are familiar with cpanel, you can access oscommerce through the fantastico and use the sql database.

Interchange is free and under constant development meaning new features are added all the time. Interchange supports both text based, MySQL and Oracle as the back end. The program can also be made to be search engine friendly and is very easy to install and setup with a large amount of support available in both docs and real time chat with developers over IRC.

Sticky me if you want me to send you the address of some sites already running Interchange.